Residential wood smoke contains fine particles and toxic air pollutants (e.g., benzene and formaldehyde). Each year, smoke from wood stoves and fireplaces contributes over 420,000 tons of fine particles throughout the country – mostly during the winter months. Nationally, residential wood combustion accounts for 44 percent of total stationary and mobile polycyclic organic matter (POM) emissions and 62 percent of the 7-polycyclic aromatic hydrocarbons (PAH), which are probable human carcinogens and are of great concern.

Long-term exposures, such as those experienced by people living for many years in areas with high particle levels, have been associated with problems such as reduced lung function and the development of chronic bronchitis—and even premature death.

Short-term exposures to particles (hours or days) can aggravate lung disease, causing asthma attacks and acute bronchitis, and may also increase susceptibility to respiratory infections.

There is also public concern about the use of older technology hydronic heaters (also known as outdoor wood boilers) and their growing use, particularly in the Northeast and Midwest. There are a number of communities where residential wood smoke can increase particle pollution to levels that cause significant health concerns (e.g., asthma attacks, heart attacks, premature death).

Several areas with wood smoke problems either exceed USEPA’s health-based standards for fine particles or are on the cusp of exceeding those standards. For example, residential wood smoke contributes 25 percent of the wintertime pollution problem in Keene, New Hampshire. In places such as Sacramento, California, and Tacoma, Washington, wood smoke makes up over 50 percent of the wintertime particle pollution problem. It may be difficult for these and other areas to meet the national health-based standards without taking steps to significantly reduce residential wood smoke.

The health benefits associated with reducing fine particle emissions, including wood smoke, are significant. If all of the old wood stoves in the U.S. were changed out to cleaner burning hearth appliances, the USEPA estimates that at least $35 billion in health benefits per year could be realized (2006$, Pope et al. (2002) PM2.5 mortality estimate). Eliminating these emissions could help avoid thousands of premature deaths, non-fatal heart attacks, chronic bronchitis and asthma attacks for example.